Apparatus for electric arc spot welding



Feb. 19, 1952 Filed July so, 1948 2 SHEETS-SHEET l m M 3 m mm u m KW IfN 4 4. MN 8E 2 mm d N. m 8 8 L 8 8 M Qw i m Feb. 19, 1952 ANDERSON2,586,140

' APPARATQS FOR ELECTRIC ARC SPOTWELDING Filed July 30, 1948 2SHEETS-SHEET 2 WELDING V MACHINE VENTOR Y NELS E. ANDERSON ATTO R N EYSPatented Feb. 19, 1952 iii/lift APPARATUS FOR ELECTRIC ARC SPOT WELDINGNelson E. Anderson, Scotch Plains, N. J., assig'norv to Air ReductionCom any, Incorporated, New York, N. Y., a corporation of New YorkApplication July 30, 1948, Serial No. 41,527

10 Claims. 1

This invention relates to electric welding and more particularly to amethod of welding and apparatus therefor.

Electric welding is widely used for many purposes, but the methods andapparatus in use have certain limitations. Among these are thediificulties encountered in spot welding, which has been accomplishedheretofore only by resistance welding methods. The electric arc method,that one face of the workpiece and is immediately withdrawn to establishan arc which is maintained for a sufficient period to ensure suitablepenetration and the melting of the metal of the parts to be joined sothat a weld is formed. The

arc is then broken, and the electrode is moved to a point at somedistance from the original weld, where the operation is repeated. Asmany spot welds may be made as is necessary to secure the partstogether. In accordance with the invent on. an inert gas such as helium,argon or the l ke is supplied continuously to surround the electrode andblanket the weld, thereby preventing the entrance of oxygen and nitrogenof the atis the application of an arc struck between the 10 mosphere andensuring the production of asound workpiece and an electrode, has notbeen adapted eld at each po t Where the a iS Struck h heretofore forjoining metals by spot welding. the workpiece. The method of operationis illus- It is the object of the present invention to proin F 6 thedrawing. in Which 5 n vide a method of spot welding metals in n cates awelding gun which is connected by a coneconomical and practical manner,ductor 6 to a time delay circuit breaker l. The

Another object of the invention is the provision latter device forms nopart Of the pr v of arc welding employing D. C. current, in which t onand is merely a Safety device t Prevent the the operation is started bytouching the workpiece maintenance of the arc for excessive p with theelectrode and immediately withdrawing The device 1 is co c d by a coductor 8 to a the electrode to strike the are. '20 welding machine 9which maybe a D. C. welding A further object of the invention is theprovigenerator- The Other D of the gehBratOr is sion of a convenient andeasily handled apparatus Co c d y a Conductor m o e WO p Ce H forapplying the electric arc in spot welding which, as illustrated,consists of two sheets or metals. plates which are to be joined by spotwelding.

Another object of the invention. is the provision T e Welding E 5consists 0i barrel a d of an apparatus for spot welding in which the a ps p l3 which may be ade of plastic. electrode and workpiece are shieldedby an inert vulcanized rubber, or other suitable material. gas toprevent oxidation and other defects in the Within the barrel 12.8. tu lis slidahly disposed welds. in a sleeve 15 which is also movablelongitudinally Other objects and advantages of the inven- 0 in t e r el.being o n in a ring 16 hic tion will be apparent as it is betterunderstood by is Secured in the barrel A Spring is disposed reference tothe following specification and acbetween the ring 16 and a flange E othe Sleeve companying drawing, in which I5 and normally biases thesleeve rearwardly in Fig. 1 is a longitudinal section through an apthebarrel- A Weaker p i g 19 is dispo e 9 paratus adapted for the practiceof the invention; t ee t e end Of t e eve 15 and a k ob 20 Fig. 2 is afront elevation of the apparatus; on the end of the tube (4. Fig. 3 isan enlarged section on the line 3-3 of At its forward end, the tube M isenlarged at Fig. 1; 2|, and the enlarged end is split to afiord fourFig. 4 is a section on the line 4-4 of Fig. 1; fingers which are adaptedto grip the electrode Fig. 5 is a detail in perspective illustrating the40 22. The enlarged end 2| is provided with a tri ger mechanism of theapparatus; and conical surface 23 which engages a similar sur- Fig. 6 isa diagrammatic illustration of the apface on the end of a collar 24which is secured to paratus in use. the sleeve IS. The enlarged end 2|,in co-opera- The invention is applicable primarily to the tion with thecollar 24, afiords a chuck adapted spot welding of sheet metal to securethe sheets to grip the electrode 22. To release the electrode to eachother. In the operation of the method, for adjustment, it is necessarymerely to push the parts to be joined are first assembled and e knob 0 iward y a t the t o Of t e clamped in proper position. The electrode,prefspring I 9. This releases the gripping fingers, erably anon-consuming electrode such as tungwhich are normally held in theposition indicated sten or the like, is then brought into contact within 1 y the Spring A e e Secured within the barrel I2, ensures alignmentof the collar 24 and permits sliding movement of the collar and thesleeve [5.

At the end of the barrel l2, a collar 28, threaded internally andexternally, is mounted on the barfitting 46 by a clamp rel. A nozzle 21,having a flange 28, is secured to the end of the barrel by a nut 29which engages the threads of the collar 28. The nozzle 21 is made ofsuitable metal adapted to withstand the workpiece H, thus ensuringmaximum shielding and protection of the weld.

A trigger 3| is pivotally mounted at 32 on the barrel I2 and operates ina recess provided for that purpose in the pistol grip [3. An arm 33 isconnected to the trigger 3| and movable therewith. A latching member 34is pivotally connected to the arm 33 at 35. A sprin 36 is secured to thelatch member 34 at 31 and to a pin 38, so that the latch member isnormally held in the position indicated in Fig. 1, in engagement withthe flange [8 on the sleeve l5. When the trigger 3! is pulled inwardly,the shoulder 39 on the latch member is moved forwardly. carrying thesleeve (5 with it, and the electrode 22 is thus projected through theopening in the end of the nozzle 21 to engage the workpiece II. Thiscloses the circuit, with the result that current fiows through aconductor in a coil 40, connected in series with the electrode holderand disposed in a magnetic frame 4 I forming a solenoid. As soon as thecurrent flows, the armature 42, having a pin 43 engaging the latchmember 34, is drawn downwardly, thus releasing the flange l8. Thereuponthe sleeve I5 is moved rearwardly by the spring I! and the arc isestablished between the electrode 22 and the workpiece.

The end of th nozzle 21 is held against the workpiece until the weld iscompleted. It'is then withdrawn and the operation is repeated to producethe next weld.

A recess 44 is provided in the butt of the pistol grip I3 to receive aflexible cable 45 which is secured to a connecting fitting 46. The cableis preferably of the type illustrated and described in the applicationof Anderson and Sullivan, Ser. No. 782,898 filed April 29, 1947, nowissued as Patent Number 2,535,187, December 26, 1950, for Electric Cablefor Welding Equipment. It consists of flexible tubes 4'! and 48,preferably'twisted and surrounded by a braided conductor 49, whichcarries the current. The conductor is in turn surrounded by a sleeve 50of suitable material such as rubber or flexible plastic, which issecured to the The tubing 48 carries the inert gas which is deliveredfrom the fitting 46 through flexible tubing 5| to a tube 52 whichextends through the collar 24 into the chamber 53 which surrounds theelectrode 22. The gas is thus delivered to the space surrounding the arcin order to maintain the desired shielding effect.

Water is delivered through the tube 41 and is V carried from the fitting46 through tubing 54 to I delivers the water to a space 63 in the collar24 which is closed by a ferrule 64. The water returns through a pipe 55and flexible tube 68, and fiows through the casing 58 about the braidedconductor 49, thus cooling the cable.

Current is supplied through the braided conductor 49 to the fitting 46to which a wire 61 is connected. The wire 61 passes through the flexibletube 66 to the collar 24 and thence to the electrode 22. As alreadyindicated, the wire 61 is disposed within the coil 40, thus ensuring release of the latch 34 as soon as the electrode 22 touches the workpiece.

The apparatus as described affords an ex tremely handy mechanism forconducting the welding operation. The operator, grasping the pistol gripl3, places the end of the nozzle against the workpiece and operates thetrigger 3| to advance the electrode 22. As soon as the electrode 22touches the work, it is released and returned by the spring I1 50 as toprovide a gap and the production of the welding arc. In one-half to twoseconds, the arc penetrates the workpiece and securely welds the partsthereof together at the point where the arc is formed. A series of sucharcs produced at spaced points along the workpiece completes the weldingoperation. Meanwhile, the shielding gas eliminates the effect of theatmosphere on the weld. The circulating cooling water maintains the tip21 and the collar 24 at a relatively low temperature, thereby preventing injury to the apparatus. The arc, when formed, is enclosedwithin the nozzle 21, and the operator is protected from heat and theglare of the arc.

Various changes may be made in the details of the apparatus as describedand in the operation of the method, without departing from the inventionor sacrificing the advantages thereof.

I claim: 1

1. In an apparatus for spot welding metals, a'

---pistol'grip, connections-between the trigger'and the electrode holderwhereby ;t l 1 e' latter is adyanced when the trigger is pulled,shame-assemtrolled byth'e flow of electric current to the-electrodeholder to retract the electrode holder.

2. In an apparatus for. spot welding metals, a barrel having a nozzleattached thereto, an electrode holder slidably supported in the barrel,a trigger and connections therefrom to the electrode holder whereby thelatter is advanced when the trigger is pulled, including a latch adaptedto hold the electrode holder in advanced position, electromagnetic meansto release the latch when electric current flows to the electrode holderand resilient means to retract the electrode holder when released.

3. In an apparatus for spot welding metals, a barrel having a nozzleattached thereto, an electrode holder, including a releasable electrodeclutch, slidably supported in the barrel, a trigger and connectionstherefrom to the electrode holder whereby the latter is advanced whenthe trigger is pulled, including a latch adapted to hold the electrodeholder in advanced position, electromagnetic means to release the latchwhen elec-- tric current fiows to theelectrode holder and resilientmeans to retract the electrode holder when released.

4. In an apparatus for spot welding metals, :1. barrel having a nozzleattached thereto, an elec trode holder within the barrel, means withinthe barrel normally exerting a force against the electrode holdertending to move it inwardly from the outer end of the barrel,manually-operable means for advancing the electrode holder against theforce of said first-mentioned means, and means connected in series withthe electrode holder and operable on flow of electric current to theelectrode holder to cause a retraction of the electrode holder.

5. In an apparatus for spot welding metals, a barrel having a nozzleattached thereto, a pistol grip connected to the barrel, an electrodeholder slidably supported in the barrel, means normally exerting a forceagainst the electrode holder tending to move it inwardly from the outerend of the barrel, a trigger carried by the pistol grip, connectionsbetween the trigger and the electrode holder operative when the triggeris pulled to advance the electrode holder, and means operated on flow ofelectric current to the electrode holder to retract the electrodeholder.

6. In an apparatus for spot welding metals, 2. barrel having a nozzleattached thereto, an electrode holder slidably supported in the barrel,means normally exerting a force against the electrode holder tending tomove it inwardly from the outer end of the barrel, a trigger,connections between the trigger and the electrode holder operative whenthe trigger is pulled to advance the electrode holder against the forceof the means tending to move it inwardly of the barrel, said connectionsincluding a latch efiective to hold the electrode holder in an advancedposition, and electromagnetic means in series with the electrode holderto release the latch when electric current flows to the electrode holderand to permit retraction of the electrode holder inwardly of the barrel.

7. In an apparatus for spot welding metals, a barrel having a nozzleattached thereto, anelectrode holder, including a releasable electrodeclutch, slidably supported in the barrel, a spring normally exerting aforce against the electrode holder tending to move it inwardly from theouter end of the barrel, a trigger, connections between the trigger andthe electrode holder operative when the trigger is pulled to advance theelectrode holder towards the outer end of the barrel, said connectionsincluding a latch efl'ective to hold the electrode holder in an advancedposition towards the outer end of the barrel, electromagnetic meansconnected in an electric circuit including the electrode andautomatically energized on the flow of electric current through theelectrode, and means operated on energization of said electromagnetic.means to release the latch and permit said spring to move the electrodeholder inwardly from the outer end of the barrel.

8. In apparatus for are spot welding, an electrode holder, a support forthe electrode holder having an end to be forced against the work duringa welding operation, means normally exerting a biasing force on theelectrode holder in a direction tending to maintain it retracted fromsaid end of the support, means for advancing the electrode holdertowards said end of the support against the force of said biasing means,and means operable on flow of electric current to the electrode holderafter it has been advanced towards said end of the support to rendersaid electrode advancing means inoperative and to permit retraction ofthe electrode holder.

9. In apparatus for are spot welding, an electrode holder, a support forthe electrode holder having an end to be forced against the work duringa welding operation, means normally exerting a biasing force on theelectrode holder in a direction tending to maintain it retracted fromsaid end of the support, means for advancing the electrode holdertowards said end ofthe support against the force of said biasing means,manually operable means for said advancing means, and means operable onflow of electric current to the electrode holder after it has beenadvanced towards said end of the support to render said electrodeadvancing means in operative and to permit retraction of the electrodeholder.

10. Arc spot welding apparatus comprising an electrode holder supportedfor movement toward and away from a workpiece to be welded, an electrodegripped by said electrode holder, means biasing said electrode holder ina direction away from said work, operating means fo advancing saidelectrode holder against said biasing means to bring said electrode intocontact with said work, and means responsive to the change in electricalconditions when said electrode contacts said work to render saidelectrode holder advancing means inoperative.

NELSON E. ANDERSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

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